This application claims the priority of German Patent Application DE 102 26 534.8 filed Jun. 14, 2002, which is incorporated herein by reference.
The invention relates to a gun in which the barrel, which is connected to a breech ring, is seated to be displaced in a barrel of a cradle.
A gun of this type is known from, for example, German Published Application No. DE 31 48 265 A1. Here, the barrel is seated in two slide-bushing bearings, which are disposed at the muzzle- and breech-side ends of the cradle barrel. A disadvantage of this type of known slide-bushing bearing is that the gun barrel, for example of a tank cannon, must rest on the lower inside edge of the bearing, as stipulated by its mass, and lifts due to the expansion of the barrel during firing. This causes the barrel to vibrate, and has a negative effect on the jump error of the respective projectile.
From German Published Patent Application No. DE 39 36 454 A1, it is known to avoid barrel vibrations during firing by using lift-effect-free bearings instead of conventional slide-bushing bearings. With the former, the gun barrel does not impact a fixed stop in the radial direction upon firing, so the barrel can expand in both the horizontal and vertical directions. For seating the barrel in the cradle barrel, four guide rails are provided, the rails being uniformly spaced over the circumference of the barrel, extending in the direction of the longitudinal axis and being embodied or formed as slide rails. The rails extend into corresponding guide grooves of the cradle barrel such that the directions of the support force and the radial barrel expansion are perpendicular to one another.
The primary drawback of this seating arrangement is that the guide rails and guide grooves extend past both bearing points, and are therefore very costly to produce. Furthermore, exchanging the barrel in such guns is a complicated and time-consuming procedure.
In view of DE 39 36 454 A1, it is the object of the invention to provide a gun that is seated to be displaced in a cradle barrel, and in which the lifting effect of the gun barrel is extensively avoided and complex guide grooves are not required in the cradle barrel, and which permits the barrel to be exchanged as in conventional gun seating arrangements.
The above object generally is achieved according to the present invention, by a gun in which the barrel, which is connected to a breech ring, is seated to be axially displaced in a cradle barrel, and wherein: the barrel is seated in a first slide-bushing bearing that is disposed at the muzzle-side end, and in a second slide-bushing bearing that is disposed at the breech ring-side end of the cradle barrel; at least the first slide-bushing bearing is constructed to be free of any lifting effect, and encompasses a barrel bushing, whose outside surface is seated to slide in the cradle barrel; on the inside, the first barrel bushing has at least three groove-shaped recesses that are uniformly spaced over the circumference; at least three tab-shaped protrusions are disposed on the gun barrel, with the protrusions extending into the respective groove-shaped recesses of the first barrel bushing; and, a predetermined amount of play is provided between the outside surface of the gun barrel, or an inside ring that supports the tab-shaped protrusions and is in a form-fit connection with the barrel, and the inner surface of the barrel bushing, and between the tab heads and the inner surface of the groove-shaped recesses of the barrel bushing, with the expansion of the gun barrel during firing being within this region of play. Further, especially advantageous embodiments of the invention are disclosed.
The invention is essentially based on the concept of arranging a slide-bushing bearing on the barrel, at least on the muzzle-side, but preferably also at the rear, with the bearing encompassing a barrel bushing in which the barrel is disposed free from a lifting effect, and whose outside surfaces slide with a form-fit in the cradle barrel that is, with the smallest possible amount of play. Consequently, unlike in DE 39 36 454 A1, the barrel is independently guided to slide both axially and radially. Similarly to DE 39 36 454 A1, the radial sliding guidance of the barrel during firing is effected by means of tab-shaped protrusions, which extend into corresponding, groove-shaped recesses of the barrel bushing and hold the barrel in the center of the barrel bushing. A predetermined amount of play is provided between the barrel, or an inside ring that is secured to the barrel against relative rotation and supports the tab-shaped protrusions, and the inside surface of the barrel bushing, with the play permitting compensation of radial expansion of the gun barrel.
Due to the absence of an axial rail guidance, the gun is less costly to produce than comparable guns. Moreover, the proposed seating arrangement of the barrel is very sturdy, and permits conventional slide bushings that are already in use to be exchanged easily for the novel, grooved barrel bushings that keep the barrel in a central position.
For exchanging the barrel quickly in the field, it has proven advantageous to connect the barrel bushing of the forward (first) slide-bushing bearing permanently to the barrel, and to connect the barrel bushing of the rear (second) slide-bushing bearing permanently to the breech ring. When the barrel is exchanged, the first barrel bushing remains on the barrel, and is disassembled with it. The second barrel bushing remains on the breech ring, and is guided centrally over its outside diameter in the cradle barrel.
If the length of the barrel bushing of the second slide-bushing bearing is selected such that the barrel bushing is pulled completely out of the cradle barrel when the barrel recoils, an additional slide bushing with a predetermined amount of fit play should be disposed at the muzzle side in the cradle barrel, in front of the rear slide-bushing bearing. The additional slide bushing assumes the task of guiding the barrel when the barrel bushing of the second slide-bushing bearing is pulled out of the cradle barrel.
The length of the second slide-bushing bearing can, however, also be selected such that the barrel bushing does not leave the cradle barrel upon recoil, so an additional slide bushing can be omitted.
Further details about and advantages of the invention ensue from the following exemplary embodiments explained in conjunction with figures.